Power booster with vacuum supply passage in position sensor housing

ABSTRACT

A vacuum brake power booster with a connecting member (23) for the connecting nozzle (2) of the vacuum line and for the vacuum non-return valve (3). The connecting member is configured in the shape of a housing for a sensing device which detects the position of the diaphragm retainer (16) within the servo-cylinder (15). The sensing device consists of a scanning pin (22) which allows rotation of a gear (9) by means of a flexible toothed rack (6). The gear allows rotation of a tap (12) on an ohmic resistance. The different voltage values generated in this manner indicated the position of the diaphragm retainer within the servo-cylinder. By an appropriate selection of components, by their configuration, by their mutual adaptation, and by the appropriate assembly of these components into a compact overall assembly unit, the contour of a conventional vacuum brake power booster is not exceeded. The mounting space requirements of the booster are thus reduced. The booster is universally applicable.

FIELD OF THE INVENTION

The present invention relates to a brake power booster for brake systemswith anti-lock and/or traction slip control. This brake power boostercomprises a servo-cylinder and a servo-piston within the servo-cylinder,the position of the servo-piston in the servo-cylinder being detected bya sensing device. In particular, the invention relates to a vacuum brakepower booster.

BACKGROUND OF THE INVENTION

The present invention can be applied to state-of-the-art vacuum brakepower boosters as described, for example, in the Brake Handbook, 8thedition, Alfred Teves GmbH, herein incorporated by reference for itsteachings in the field of brake systems. Specific reference to vacuumbrake power boosters is found on pages 94 et seq. of this handbook.

The present invention also can be applied to brake systems which areequipped with anti-block and/or traction slip control. A pneumatic brakepower booster for a brake system which has an anti-lock and/or tractionslip control is described, for example, in German patent application No.P 3815768.3.

The aforesaid patent application discloses a pneumatic brake powerbooster, and in particular a vacuum brake power booster for a brakepressure control device. The patent specifically discloses an anti-blockcontrol device (ABS device) or a traction slip control device (TSCdevice) for automotive vehicles with a master cylinder, wheel cylinders,at least one pump for the positioning of at least one piston of themaster cylinder, a pressure modulator which modulates the pressure inthe wheel cylinders during the control modus, and an electroniccontroller which processes wheel sensor signals to actuating signals forthe inlet valves and for the shut-off valves of the pressure modulator.The booster is comprised of a housing, a piston element, a diaphragmretainer in particular, and a diaphragm, preferably of a rollingdiaphragm which sealingly connects the piston element to the housing andwhich permits movements of the piston element relative to the housing,the piston element being in active connection with the brake pedal.

It is proposed in the aforesaid German patent application that thehousing, the piston element, in particular the diaphragm retainer, andthe diaphragm preferably the rolling diaphragm, are configured as partof a travel switch for the control of the pump, in particular throughthe electronic controller.

It is shown by FIG. 4 of the German patent application that a travelsensor housing for a travel sensor 64 projects beyond the outer contourof the vacuum brake power booster.

SUMMARY OF THE INVENTION

It is an object of the present invention to eliminate the projection ofthe travel sensor from the contour of the booster.

Because of its outer contour, the inventive booster is virtuallyuniversally mountable.

The vehicle manufacturers repeatedly change their specificationsregarding the mounting spaces for brake power boosters. Thesemodifications involve the location, the size, and the configuration ofthe mounting space.

It is another object of the present invention to be able to adapt tochanges of this kind without any major expenditure.

The inventive booster therefore offers maximum independence with regardto the space offered by the automotive vehicle manufacturers.

In addition, the booster housings can be standardized to a few standardtypes. Thus, a reduction in the mounting space requirements of thebooster are realized.

Furthermore, the susceptibility of the vacuum brake power booster tostrain during transport and assembly, due in particular to theprojection of the travel sensor, is avoided.

It is a further object of the present invention to simplify theexchangeability and assembly of the vacuum brake power booster.

Moreover, the structural prerequisites are fulfilled by uniting theprior-art vacuum nozzle and the prior-art non-return valve with thesensor housing so as to form a compact assembly unit.

According to the invention, these and other objects are achieved byconfiguring one portion of the wall of the servo-cylinder in the shapeof a housing for at least one part of the sensing device.

In a brake power booster with a connecting member for servo-fluid whichis positioned in the wall of the servo-cylinder, it is proposed that atleast part of the sensing device is accommodated within the connectingmember.

In this context, the connecting member can be configured as a housingfor at least part of the sensing device.

In one preferred embodiment, the sensing device is composed of ascanning member for the servo-piston which actuates a gearing of anelectric element to generate a sensor signal (electric part) which isactuated by the gearing. At least part of the guide for the scanningmember, the gearing, and the electric element are accommodated in theconnecting member.

Along the lines of a further development of the aforesaid embodiment,the gearing comprises a flexible toothed rack and a gear which are ininteracting connection with each other.

The scanning member may be comprised of a scanning pin which scans theposition of the servo-piston and is connected to the flexible toothedrack, and a telescopic device to guide the scanning pin.

To ensure a safe contact in a determined range between the scanning pinand the servo-piston, it is proposed that a spring member, in particulara helical spring, is provided which keeps the scanning pin in abutmentwith the servo-piston through the gearing.

The electric part of the sensing device can consist of a rotarypotentiometer which is actuated by the gear. The baseplate which will bedescribed herein and the gear can be configured in one part.

The rotary potentiometer may be structured so as to be comprised of abaseplate which is fabricated of an electrically non-conductive materialand on which an ohmic resistance in a circular arc-shaped configuration(not closed circuit) is accommodated, and a tapping member which is inphysical contact with the ohmic resistance and which is adapted toperform a particularly circular arc-shaped movement relative to theohmic resistance. Two alternatives are proposed in this context.According to the first alternative, the tapping member is arranged so asto be rotatable by the gear relative to the baseplate with the ohmicresistance. According to the second alternative, the baseplate with theohmic resistance is arranged so as to be rotatable by the gear relativeto the tapping member. If and when the material of the ohmic resistanceis adapted to transmit force then a baseplate will be unnecessary. Theohmic resistance may also be positioned on the gear.

The above-mentioned connecting member, which is preferably made ofplastic material, may be configured in the shape of a housing withinwhich a common shaft for the gear and for the rotary potentiometer isaccommodated. Furthermore, a slide rail for the toothed rack may beaccommodated, particularly by being molded in, within the housing.

An especially compact design is achieved in that the connecting memberis configured in the shape of an accommodating element for the vacuumnon-return valve and/or for the vacuum connecting nozzle. In thiscontext, the vacuum connecting nozzle is accommodated within theconnecting member so as to be rotatable.

In order to safeguard against rotation of the connecting member withrespect to the servo-cylinder, the connecting member is in anon-circular (e.g. elliptical or oval) configuration in the range of itscoupling to the servo-cylinder. In another embodiment, the connectingmember is configured in the shape of a housing and is positioned at aportion of the wall of the servo-cylinder in such a manner that thescanning pin performs paraxial movements with respect to the axis of thebrake power booster. The connecting member may have a circularconfiguration. A safeguard against rotation is not indispensable. Alow-cost assembly of the booster is achieved in that at its outercircumference and in the range of its connection with the opening in thewall of the servo-cylinder the connecting member is furnished with abuttoning-in collar preferably presenting a saw tooth-shaped externalprofile, and in that an elastic sealing plug is positioned between theopening in the wall of the servo-cylinder and the buttoning-in collar.

According to a further embodiment of the invention, the connectingmember is configured as a vacuum connecting valve and is provided with asuction duct which ends up in a vacuum chamber, is positioned in a valvehousing, and into which a movable element of the position sensor isintroduced telescopingly, covering part of the cross sectional area ofthe suction duct. An opening already exists in the vacuum connectingvalve due to the suction duct, into which the movable element of theposition sensor can be introduced without any major difficulty. Thediameter of the suction duct may be increased only slightly in order tomake available an equal flow cross section for the air which flows outof the vacuum chamber.

Advantageously, the movable element is positioned centrally in thesuction duct. As a result, the flow behavior within the suction ductwill change only insignificantly. Furthermore, it will not be imperativein the event of assembly of the vacuum connecting valve to observe adetermined angular position of the vacuum connecting valve in respect ofthe booster housing. The movable element will be in the same position inany angular arrangement.

In one preferred embodiment, a sensor is positioned in the vacuumconnecting valve which generates an electric output signal depending onthe position of the movable element. Indeed, an electric output signalis very easy to be conveyed onward and to be processed. In thisconfiguration, the electric signal may also be generated contactlesslyby, for example, an inductive, capacitive or optical coupling.

In this embodiment, the sensor is configured in the shape of aresistance track on which a slider which is driven by the movableelement slides. In other words, the position sensor is furnished with apotentiometer whose center tap is moved by the movable element. Thevoltage drop between the center tap, on one hand, and the one or theother connection of the potentiometer, on the other hand, will thenallow drawing a conclusion on the position assumed by the movableelement of the position sensor and, thus, of the diaphragm.

In another preferred embodiment, the electric sensor is provided with aplurality of contact surfaces which are separated from one anotherelectrically and which in the event of a movement of the movable elementcome into contact one after the other with a movable contact beingdriven by the movable element. In this way, a continuous resolution ofthe position of the movable element will no longer be possible. This is,however, not necessary. For all normal applications it is sufficientwhen there is a possibility to find out whether or not the diaphragmretainer has assumed a position within one of several ranges. Theresolution is influenced by the number of contact surfaces. Discretesignals will then be available at the output of the sensor which may,for example, also be processed further digitally.

In another preferred embodiment, the movable element is prestressed by afirst spring in the direction of its position of rest. A telescopicelement is positioned in the movable element which is prestressed in thedirection of its position of rest by a second spring acting in the samedirection, the second spring being much more rigid than the firstspring. In this configuration, in its position of rest, the telescopicelement projects out of the movable element and represents the elementon which the diaphragm retainer acts. When the diaphragm retainer ismoved into the vacuum chamber as a result of a movement of the brakepedal, initially, the movable element jointly with the telescopicelement is moved contrasting the force of the first spring because thesecond spring is much more rigid than the first spring and practicallycreates a rigid coupling between the telescopic element and the movableelement. When the first element reaches a stop, the telescopic elementmay be driven into the first element contrasting the force of the secondspring. In this context, it is sufficient when the contact, i.e. theslider, is positioned at the movable element. In this way it is nolonger possible to cover the total movement of the diaphragm retainerfrom one final position into the other. This is, however, not necessary.It is sufficient to monitor the position of the diaphragm retainer onlywithin a determined range. Any movement of the brake pedal and thus ofthe diaphragm retainer beyond this range is unimportant for furtherprocessing.

In yet another preferred embodiment, the vacuum connecting valve isprovided with a suction nozzle which extends at a predetermined anglewith respect to the suction duct, the suction nozzle being rotatablerelative to the housing. Thus, the suction nozzle does not projectvertically out of the housing of the brake power booster. Rather, itextends parallel or at a slight angle, for example, with respect to thefront side of the housing of the vacuum brake power booster. Thisreduces the space requirements and facilitates the assembly of a vacuumsuction hose which extends, for example, from the engine air suctionnozzle to the carburetor. Because the suction nozzle and the vacuumsuction valve with its position sensor cannot be installed in thehousing of the brake power booster and must be installed in a certainposition, the suction nozzle is rotatable with respect to the valvehousing. Thus, the suction nozzle points invariably into the samedirection. The same holds true of an embodiment in which an electricconnecting device is provided which is fixed to the valve housing andwhich is rotatable in its fixing position in respect of the valvehousing. The mounting position of the vacuum connecting valve may alsobe independent of the position of the electric lines which are to beconnected to the vacuum connecting valve for the electric supply of theposition sensor and for the transmission of information from theposition sensor.

In this context, the valve housing is preferably furnished with aplurality of sliding contact rings which are electrically connected tothe sensor and the connecting device is provided with a correspondingnumber of sliding contacts which adhere to the sliding contact rings.This means that the sliding contact rings lead the electric supply andinformation connections to the surface of the vacuum connecting valveand once completely round about the vacuum connecting valve, so that theconnecting device may be fixed in any angular position with respect tothe valve housing.

The following advantages are offered by the invention:

The projection of the travel sensor from the contour of the booster iseliminated. The inventive booster is universally applicable.

The booster is largely independent of the space offered for it by theautomotive vehicle manufacturer. In addition, a standardization of thebooster housings to a few standard types is attained. The mounting spacerequirements are reduced in general.

The travel sensor thus forms a structural unit with the vacuumconnecting valve. Accordingly, the contour of the housing of the brakepower booster is no longer influenced by the travel sensor. Theincorporation of the travel sensor in the housing of the brake powerbooster no longer affects the space requirements. The brake powerbooster may be handled and mounted with greater ease because fewer partsproject outwardly. Furthermore, the travel sensor is given a protectedaccommodation within the vacuum connecting valve, so that the risk ofdamaging any projecting parts of the position sensor is minimized. Noadditional hole for the position sensor needs to be provided in thehousing of the brake power booster. This facilitates the sealing of thebrake power booster and reduces the risk of leakage in the vacuumchamber, which is, indeed, increased by each additional opening andwhich affects the safety of driving of the vehicle to a great extent.Finally, a considerable simplification of mounting results. The travelsensor may be pre-assembled in the vacuum connecting valve. The vacuumconnecting valve can then be incorporated in the housing of the brakepower booster for final assembly of the brake power booster.

Further details of the invention, of the objects and of the advantagesoffered will be revealed by the following description of one embodimentof the invention which is made with reference to ten figures.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 shows the pneumatic servo-element of a vacuum brake power boosterwith a travel sensor housing in a sectional representation;

FIG. 2 shows a travel sensor housing with a vacuum non-return valve anda vacuum connecting nozzle in a sectional representation, the sectionrunning along the cross-sectional line II--II in FIG. 4;

FIG. 3 shows a view of the subject matter of FIG. 2 in the direction ofthe arrow III in FIG. 2;

FIG. 4 shows a view, partially in section, of the subject matter of FIG.2 in the direction of the arrow IV in FIG. 2;

FIG. 5 shows an alterative arrangement of the travel sensor housing ofFIG. 1;

FIG. 6 shows another embodiment of the travel sensor with a vacuumnon-return valve and a vacuum connecting nozzle in a sectionalrepresentation;

FIG. 7 shows a sectional view along the line III--III in FIG. 6;

FIG. 8 shows a further embodiment of the travel sensor with a vacuumnon-return valve and a vacuum connecting nozzle in a sectionalrepresentation;

FIG. 9 shows a sectional view along the line V--V in FIG. 8; and

FIG. 10 shows an electric connecting device.

DETAILED DESCRIPTION OF THE INVENTION

In FIGS. 1 to 4, a travel sensor is shown which is identified in itsentirety by reference numeral 1. IT is combined with a suction nozzle,respectively with a vacuum connecting nozzle 2, see FIG. 2, and with avacuum non-return valve 3, see FIG. 2. This combination is accommodatedin the housing wall 4, see FIG. 1, of a vacuum servo-cylinder.

The travel sensor is comprised of a rotary potentiometer 5, see FIG. 4,which is actuated by a flexible toothed rack 6, see FIG. 2, which isguided by a telescopic device 7.

The toothed rack is guided, beyond the telescopic device, also by aslide rail 8. The toothed rack rotates gear 9. Gear 9 rotates the tap 12of the rotary potentiometer through an entrainment pin 11.

In addition, a helical spring 13 is provided which in the event of therelease of the brake resets all actuating elements of the travel sensorwithout play.

The outer buttoning-in collar 14 of the travel sensor 1 has an ovalshape as a safeguard against rotation.

In detail, the vacuum brake power booster shown in FIG. 1 is composed ofthe servo-cylinder which is identified in its entirety by referencenumeral 15, and of a servo-piston 16.

The servo-cylinder consists of two cups 17, 18 which are coupled to eachother in the range of their outer periphery. The servo-piston 16 isconfigurated in the shape of a diaphragm retainer which is sealingly andaxially moveably fixed in the servo-cylinder by means of a rollingdiaphragm 19.

Two positions of the servo-piston, respectively of the diaphragmretainer are shown in FIG. 1 which bear the reference numerals 16, 20.Reference numeral 16 denotes the diaphragm retainer in its retractedright position when the brake is in the released condition. Referencenumeral 20 denotes the position of the diaphragm retainer in its leftextreme position. The double arrow 21 denotes the stroke of thediaphragm retainer.

Reference numeral 22 denotes a scanning pin which touches the diaphragmretainer only in the event of a braking action. In another embodiment,the scanning pin is permanently abutted with the diaphragm retainer.

Reference numeral 2 denotes the connecting member for the vacuumconnection which is configured in the shape of a housing for the travelsensor. Reference numeral 29 is a sealing plug for the connecting member23.

It will be seen from FIG. 2 that the scanning pin 22 is coupled to theflexible toothed rack 6. The toothed rack itself is guided in atelescopic device which is composed of three telescopic tubes 24, 25,26. Further guidance of the flexible toothed rack within the housing 23is safeguarded by the slide rail 8 which is molded in the housing.

As will be appreciated particularly from FIG. 2 and from FIG. 4, thetoothed rack 6 mates with the gear 9. The potential directions ofmovement of the gear are indicated in FIG. 2 by the double arrow 27.

It will be seen from FIG. 2 that the buttoning-in collar which isdenoted in its entirety by reference numeral 14 presents a saw-toothprofile 28. As is illustrated, the collar itself is designed oval-shapedor elliptical, to safeguard against rotation of the housing 23 withrespect to the wall of the servo-cylinder.

A sealing plug 29 which consists of elastic material is positionedbetween the housing wall 4 and the housing 23.

As shown by FIG. 2, a vacuum non-return valve 3 is fixed to the housing23. A vacuum connecting nozzle 2 is attached to the non-return valve bymolding. The assembly which is comprised of the non-return valve and ofthe vacuum connecting nozzle is rotatable with respect to the housing 23of the travel sensor. This rotatability is illustrated in FIG. 3 by thearrows 30, 31 and in FIG. 4 by the arrows 32, 33.

Owing to the rotatability of the vacuum connecting nozzle, an easyadaptation to the mounting conditions predetermined by the automotivevehicle manufacturer, such as, for example, the dislocation of thevacuum line, is rendered possible.

The flexible toothed rack 6 is shown in a sectional representation inFIG. 4. As described above, it is in active connection with the gear 9,see FIG. 4. In the event of a rotation of the gear, the hub element 34which is supported on the shaft 10 is rotated by means of theentrainment pin 11. The tap 12 is rigidly coupled to the hub element.

The tap 12 is in physical contact with the ohmic resistance 35 which ispositioned on a baseplate 36 which consists of electricallynon-conductive material and is coupled to the housing. A determinedsection of the ohmic resistance having a circular arc-shapedconfiguration will become effective depending on the position of the tapon the ohmic resistance. This will lead to different output voltages atthe plug connection 37, see FIG. 3. These output voltages are measuredvalues which indicate the position of the diaphragm retainer within theservo-cylinder.

As will be appreciated from FIG. 4, the gear 9 has a further entrainmentpin 38 which is coupled to the one end of the helical spring 13.

The other end of the helical spring is coupled to housing 23. Thehelical spring acts in the sense that, as has been described above, thescanning pin is maintained in abutment against the diaphragm retainerthrough the gear and the flexible toothed rack.

In the embodiment described as yet, the baseplate consisting ofnon-conductive material and the ohmic resistance positioned on it arearranged stationarily within the housing, whereas the tap moves.

In another embodiment which is not illustrated in the drawings, thebaseplate with the ohmic resistance is moved by the gear and that thetap is configurated as a stationary member.

In further embodiments of the invention, the inventive sensor housingmay be designed without a vacuum non-return valve and without a vacuumconnecting nozzle. A structural solution of this kind becomes convenientparticularly when and if the vacuum non-return valve is to be arrangedin the suction line in the range of the suction nozzle of the engine. Inthat case, the travel sensor housing is configured in such a way that itis practically positioned in the contour of the cylinder of the booster.

A further embodiment of the invention is illustrated in FIG. 5. Theconnecting member 40 which is configured in the shape of a housing isdisposed at a portion 39 of the wall 41 of the servo-cylinder in such amanner that the scanning pin 44 performs paraxial movements in respectof the axis 45 of the brake power booster.

The tongue 42 illustrated in FIG. 5 which projects into a groove 43 ofthe connecting member 40 represents another potential safeguard againstrotation in case of an inclined housing and a circular connectingmember.

Paraxial movements in case of a circular connecting member 40 areensured, for example, even without safeguard against rotation in thatthe portion 39 of the wall 41 of the servo-cylinder is arranged suchthat it is disposed at right angles with the axis 45 of the brake powerbooster.

The particular advantage offered by this embodiment which is not shownin the drawing consists in that on rotation of the vacuum nozzleconnected to the sensor housing 40, the scanning pin 44 remains paraxialin respect of the axis of the booster and does not assume an angularposition.

A further embodiment of a vacuum connecting valve 109 is illustrated inFIGS. 6 and 7. The vacuum connecting valve is provided with a non-returnvalve 112 through which air may be aspirated over a suction duct 114 anda suction nozzle 113 from the vacuum chamber of the vacuum brake powerbooster which is not shown in the drawing. Suction duct 114 ispositioned within a valve housing 115.

The travel sensor 110 which is accommodated within the valve housing 115is comprised of a movable element 111 which, in the event of actuation,is in contact with the diaphragm retainer 16 shown in FIG. 1. In theposition of rest of diaphragm retainer 16, a play between the movableelement 111 and the diaphragm retainer 16 may exist. Upon actuation, thediaphragm retainer 16 is moved in the direction of the master brakecylinder (not shown in the drawing), urging the movable element 111 intothe valve housing 115.

Movable element 111 is furnished with a first telescopic element 116which is adapted to be telescoped into the housing 115, contrasting theforce of a spring 117. During this operation, first telescopic element116 is guided within the housing by supports 140. The first telescopicelement 116 covers part of the flow cross sectional area of the suctionduct 114 and is retained roughly centrally within the suction duct 114.The air aspirated from the vacuum chamber may flow off to the suctionnozzle 113 through the annular slot which is formed between the firsttelescopic element 116 and the valve housing 115. The spring 117 takessupport at a stop 125 which is formed in the housing, respectively, atan element which is rigidly coupled to the latter. Within firsttelescopic element 116, a second telescopic element 118 is positionedwhich is adapted to be telescoped into the first telescopic element 116.The second telescopic element 118 is retained in its position of rest bya second spring 119. In this configuration, second spring 119 is guidedin its position by a guide stud 124. Second spring 119 is considerablymore rigid than the first spring 117, that is to say, it has aconsiderably higher spring tension. When a force is brought to bear bythe diaphragm retainer 16 on the second telescopic element 118,initially the first telescopic element 116 will be urged into the valvehousing 115 against the force 117. On account of the elevated springtension of the second spring 119, a practically rigid coupling comesabout between the first telescopic element 116 and the second telescopicelement 118. Only when the first telescopic element 116 cannot be urgedfurther into the valve housing 115, for example because the first spring117 is already completely compressed while the pressure on the secondtelescopic element 118 which is applied by the diaphragm retainer 16 is,however, increased further, then the second telescopic element 118 willmove into the first telescopic element 116.

A slider 120 is fixed to the first telescopic element 116. The slider120 is passed across a resistance track 121 in the event of a movementof the first telescopic element 116. The slider 120 and at least one endof resistance track 121 are each connected to one electric connection122, 123. In the event of a movement of the slider 120, which is causedby a movement of the first telescopic element 116, the electricresistance between the connections 122, 123 will thus change. Then ,thecurrent flow through the electric connections 122, 123, respectively andthe voltage between them is a measure which indicates at which point theslider 120 has come to be positioned on the resistance track 121. At thesame time, this will allow determining how far the first telescopicelement 116 has been urged into the valve housing 115, which provides adetermination of the position of the diaphragm retainer 16 and the brakepedal which is not shown in the drawing. Across the range of motion ofthe first telescopic element 116, the position of the slider 120 on theresistance track 121 is, indeed, a direct measure of the position of thediaphragm retainer 16 within the housing of the brake power booster. Themovement of the telescopic element 116, to the right is limited by astop 126 which is configured in the valve housing 115.

The suction nozzle 113 is locked in the valve housing 115, for exampleby a snap-type coupling 128. A seal 127 is positioned between thesuction nozzle 113 and the valve housing 115, which prevents the vacuumgenerated within the suction nozzle 113 from being cancelled orattenuated again by the intake of air from the atmosphere. Suctionnozzle 113 is disposed at an angle with respect to the suction duct 114.In the example illustrated, the angle is approximately 90 degrees. Inthis way, the suction nozzle 113 will be oriented nearly parallel to thefront side of the booster housing 4.

A suction hose which is not shown in the drawing and which conveys thevacuum from the engine suction duct to the brake power booster can bepushed onto the suction nozzle 113 from above or from the side. Thesuction nozzle 113 is arranged rotatably in the valve housing 115 inorder to achieve a preferred mounting position for the suction nozzle113. This means that independently of the position of rotation of thevalve housing 115 within the booster housing 4, the suction nozzle 113will always allow adjustment such that it points, for example, in anupward direction. The aim achieved in this manner is that the electricconnections 122, 123 and the suction nozzle 113 may be mounted inpractically any angular position in respect of one another.

FIGS. 8 to 10 show another embodiment of a vacuum connecting valve, inwhich components which correspond to those in FIGS. 6 and 7 are givenreference numerals increased by 100.

In contrast with the embodiment in FIGS. 6 and 7, the suction nozzle 213is not disposed rotatably but stationarily at the valve housing 215. Inorder to achieve the result that the angular position between thesuction nozzle 213 and the electric connections 222, 223 is adjustableat option, the electric connections 222, 223 are rotatable on the valvehousing 215. For this purpose, two slide tracks 234 are provided on thesurface of the valve housing 215 which extend in circumferentialdirection about the whole valve housing 215, their beginnings and theirends being connected to each other. An electric connector element 237 isfurnished with sliding contacts 235, 236 which are connected to theelectric connections 222, 223. The sliding contacts 235, 236 slide onthe two slide tracks in any angular position of the connector element237 and, therefore, ensure the electric contact between the slide tracks234 and the electric connections 222, 223 in any angular position.

Three contact surfaces 230, 231, 232 which are separated from oneanother are provided in lieu of the slide track 234 of the firstembodiment. The distances between the individual contact surfaces 230,231, 232 are shown exaggerated in FIG. 8. In reality, the contactsurfaces are very close to one another, being, however, electricallyisolated from one another. At the first telescopic element 216, amovable contact 233 is provided which is rigidly coupled to the firsttelescopic element 216. When the movable element 211 moves, the movablecontact will come in contact with the contact surfaces 232, 231, and 230one after the other. Making contact between the movable contact and thecontact surfaces allows electrical monitoring. When and if, for example,the movable contact 233 is in contact with the contact surface 231, thenthis will indicate how far the movable element 211 has been urged intothe housing 115 and, thus, it will indicate movement performed by thediaphragm retainer 16, respectively by the brake pedal. The currentsflowing through the contact surfaces 230, 231, 232, respectively and thevoltage drops taking place at resistances which are connected with thecontact surfaces, furnish the information about which the contactsurface is in contact with the movable contact 233 at any given moment.Since discrete values are used here, these values will, indeed, easilyallow further digital processing

We claim:
 1. A brake power booster for brake systems with anti-lockand/or traction slip control, which comprises a servo-cylinder having awall defining a portion of a housing of said servo-cylinder and aservo-piston within said servo-cylinder housing, the position of saidservo-piston in said servo-cylinder housing being detected by a sensingdevice characterized in that a portion of the wall of said servocylinderis configured as a sensing device housing for at lest part of saidsensing device, and a connecting member for a servo-fluid is positionedin the wall of said servo-cylinder, which connecting member accommodatesat least part of said sensing device.
 2. A vacuum brake power booster asclaimed in claim 1 characterized in that said connecting member isconfigured as a housing for at least part of said sensing device.
 3. Abrake power booster as claimed in claim 2, characterized in that saidmovable element is positioned centrically within said suction duct.
 4. Avacuum brake power booster as claimed in claim 1, characterized in thatsaid sensing device is composed of a scanning member which actuates agearing, of an electric element to generate a sensor signal, which isactuated by said gearing, in that at least part of the guide for saidscanning member, said gearing, and said electric element areaccommodated in said connecting member.
 5. A vacuum brake power boosteras claimed in claim 4, characterized in that said gearing comprises aflexible toothed rack and a gear which are in interacting connectionwith each other.
 6. A vacuum brake power booster as claimed in claim 5,characterized in that said scanning member is comprised of a scanningpin which is connected to said flexible toothed rack and of a telescopicdevice to guide said scanning pin.
 7. A vacuum brake power booster asclaimed in claim 1, characterized in that a spring member is providedwhich keeps said scanning pin in abutment with said servo-piston throughsaid gearing.
 8. A vacuum brake power booster as claimed in claim 7,characterized in that said electric part consists of a rotarypotentiometer which is actuated by said gear.
 9. A vacuum brake powerbooster as claimed in claim 8, characterized in that a baseplate for thesaid rotary potentiometer is provided which forms one component togetherwith said gear.
 10. A vacuum brake power booster as claimed in claim 9,characterized in that said rotary potentiometer is comprised of saidbaseplate which is fabricated of an electrically nonconductive materialand on which an ohmic resistance of particularly circular arc-shapedconfiguration is accommodated, and of a tapping member which is inphysical contact with said ohmic resistance and which is adapted toperform a particularly circular arc-shaped movement relative to saidohmic resistance.
 11. A vacuum brake power booster as claimed in claim10, characterized in that said tapping member is arranged so as to berotatable by said gear relative to said baseplate with said ohmicresistance.
 12. A vacuum brake power booster as claimed in claim 10,characterized in that said baseplate with said ohmic resistance isarranged so as to be rotatable by said gear relative to the said tappingmember.
 13. A vacuum brake power booster as claimed in claim 10,characterized in that said ohmic resistance is positioned on said gear.14. A vacuum brake power booster as claimed in claim 10, characterizedin that said gear and said rotatable baseplate of said rotarypotentiometer are configurated one-part.
 15. A vacuum brake powerbooster as claimed in claim 6, characterized in that said connectingmember is configured as a housing and is positioned at a portion of thewall of said servo-cylinder in such a manner that said scanning pinperforms paraxial movements in respect of the axis of the brake powerbooster.
 16. A vacuum brake power booster as claimed in claim 8,characterized in that said connecting member is made of plastic materialand is configured as a hosing within which a common shaft for said gearand said rotary potentiometer is accommodated.
 17. A vacuum brake powerbooster as claimed in claim 16, characterized in that said connectingmember is configured as a housing within which a slide rail for saidtoothed rack is accommodated.
 18. A vacuum brake power booster asclaimed in claim 1, characterized in that said connecting member isconfigured as an accommodating element for a vacuum non-return valve.19. A vacuum brake power booster as claimed in claim 1, characterized inthat said connecting member is configured as an accommodating elementfor a vacuum connecting nozzle.
 20. A vacuum brake power booster asclaimed in claim 19, characterized in that said vacuum connecting nozzleis accommodated within said connecting member such as to be rotatable.21. A vacuum brake power booster as claimed in claim 1, characterized inthat the range of its coupling to said servo-cylinder said connectingmember presents a non-circular configuration.
 22. A vacuum brake powerbooster as claimed in claim 1, characterized in that at its outercircumference and in the range of its connection with said wall of saidservo-cylinder, said connecting member is furnished with a buttoning-incollar presenting a saw tooth-shaped external profile, in that anelastic sealing plug is positioned between said opening in said wall ofsaid servo-cylinder and said buttoning-in collar.
 23. A vacuum brakepower booster as claimed in claim 1, characterized in that saidconnecting member is configured as a vacuum connecting valve and isprovided with a suction duct which ends up in a vacuum chamber, ispositioned in a valve housing, and into which a movable element of saidsensing device is introduced telescopingly, covering part of the crosssectional area of suction.
 24. A brake power booster as claimed in claim23, characterized in that said sensing device is positioned in saidvacuum connecting valve which generates an electric output signaldepending on the position of the said movable element.
 25. A brake powerbooster as claimed in claim 24, characterized in that said sensingdevice is configured as a resistance track on which a slider slideswhich is driven by said movable element.
 26. A vacuum brake powerbooster as claimed in claim 24, characterized in that said sensingdevice is provided with a plurality of contact surfaces which areseparated from one another electrically and which in the event of amovement of the said movable element come in touch one after the otherwith a movable contact being driven by the said movable element.
 27. Abrake power booster as claimed in claim 23, characterized in that saidmovable element is prestressed by a first spring in the direction of itsposition of rest, in that in said movable element a telescopic elementis positioned which is prestressed in the direction of its position ofrest by a second spring acting in the same direction, and in that saidsecond spring is much more rigid than said first spring.
 28. A vacuumbrake power booster as claimed in claim 37, characterized in that saidvacuum connecting valve is provided with a suction nozzle which extendsat a predetermined angle in respect of said suction duct, said suctionnozzle being rotatable relative to said valve housing.
 29. A vacuumbrake power booster as claimed in claims 28, characterized in that anelectric connecting device is provided which is fixed to said valvehousing and which is rotatable into its fixing position in respect ofsaid valve housing.
 30. A vacuum brake power booster as claimed in claim29, characterized in that said valve housing is furnished with aplurality of sliding contact rings which are electrically connected tosaid sensing device and in that said connecting device is provided witha corresponding number of sliding contacts which are adhering onto saidsliding contact rings.
 31. A brake power booster comprising:aservo-cylinder having a wall defining a portion of a housing of saidservo-cylinder; a servo-piston located within said servo-cylinderhousing; sensing means for detecting the position of said servo-pistonwithin said servo-cylinder housing; and a sensing means housingcontaining at least a portion of said sensing means and positioned insaid wall of said servo-cylinder housing to form a portion of said wall,wherein said sensing means housing includes a connecting memberpositioned in said wall of said servocylinder and through whichservo-fluid passes.
 32. A brake power booster according to claim 31wherein said sensing means include:(a) a movable scanning memberresponsive to movement of said servo-piston, (b) a guide for saidscanning member, (c) a gearing actuated by said scanning member, and (d)signal generating means actuated by said gearing for generating a sensorsignal representative of movement of said servo-piston.
 33. A brakepower booster according to claim 32 wherein at least part of said guide,said gearing and said signal generating means are positioned within saidconnecting means.
 34. A brake power booster according to claim 33wherein said gearing includes:(a) a gear, and (b) a flexible toothedrack engaged by said gear.
 35. A brake power booster according to claim35 wherein said scanning member is a pin which is coupled to saidflexible toothed rack and said guide is a telescoping unit through whichsaid flexible toothed rack and said pin extend.
 36. A brake powerbooster according to claim 35 further including spring means for urgingsaid pin to maintain contact with said servo-piston.
 37. A brake powerbooster according to claim 36 wherein said spring means include ahelical spring acting upon said gearing.
 38. A brake power boosteraccording to claim 37 wherein said signal generating means include:(a)an ohmic resistance of circular arcshaped configuration located on saidgear, and (b) a tapping member in contact with said ohmic resistance.39. A brake power booster according to claim 35 wherein said signalgenerating means include a rotary potentiometer coupled to said gear.40. A brake power booster according to claim 39 wherein said rotarypotentiometer includes:(a) a baseplate fabricated of an electricallynon-conductive material, (b) an ohmic resistance of circular arcshapedconfiguration located on said baseplate, and (c) a tapping member incontact with said ohmic resistancesaid tapping member and said ohmicresistance adapted for circular arc-shaped relative movement.
 41. Abrake power booster according to claim 40 wherein said tapping member isrotatable by said gear.
 42. A brake power booster according to claim 40wherein said baseplate is rotatable by said gear.
 43. A brake powerbooster according to claim 10 wherein said sensing means include acommon shaft positioned within said connecting member and upon whichsaid gear and said rotary potentiometer are mounted.
 44. A brake powerbooster according to claim 43 wherein said connecting member includes aslide rail along which said flexible toothed rack moves.
 45. A brakepower booster according to claim 35, wherein said brake power boosterdefines an axis and said pin moves parallel to said axis.
 46. A brakepower booster according to claim 40 wherein said gear and said baseplateof aid potentiometer are formed as a single unit.
 47. A brake powerbooster according to claim 31 further including a vacuum non-returnvalve positioned in said connecting member.
 48. A brake power boosteraccording to claim 31 further including a vacuum connecting nozzlepositioned in said connecting member.
 49. A brake power boosteraccording to claim 48 wherein said vacuum connecting nozzle is rotatablerelative to said connecting member.
 50. A brake power booster accordingclaim 31, wherein said connecting member includes a non-circular partwhich is positioned in said wall of said servocylinder.
 51. A brakepower booster according to claim 32 wherein said connecting member has asaw tooth-shaped external profile and said brake power booster furtherincludes an elastic sealing plug interposed between said sawtooth-shaped external profile of said connecting member collar and saidwall of said servo-cylinder.
 52. A brake power booster according toclaim 32 wherein:(a) said power brake booster has a vacuum chamber, (b)said connecting member is a vacuum connecting valve having a suctionduct opening into said vacuum chamber, and (c) said sensing meansinclude a telescoping unit extending through said suction duct.
 53. Abrake power booster according to claim 52 wherein said telescoping unitis positioned centrally within said suction duct.
 54. A brake powerbooster according to claim 53 wherein said sensing means include:(a) aresistance track, and (b) a sliding element coupled to said telescopingunit and movable along said resistance track.
 55. A brake power boosteraccording to claim 53 wherein said sensing means include:(a) a pluralityof contact surfaces electrically isolated from one another, and (b) acontact element coupled to said telescoping unit and movable from one ofsaid contact surfaces to another.
 56. A brake power booster according toclaim 52 further including:(a) a first spring urging said telescopingunit to move to its position of rest, and (b) a second spring urgingsaid telescoping unit to move to its position of rest said second springbeing more rigid than said first spring.
 57. A brake power boosteraccording to claim 52 wherein said vacuum connecting valve includes arotatably mounted suction nozzle extending at a predetermined anglerelative to said suction duct.
 58. A brake power booster according toclaim 57 wherein said sensing means include an electric connectingdevice rotatable mounted on said vacuum connecting valve.
 59. A brakepower booster according to claim 58 wherein said vacuum connecting valveincludes a plurality of sliding contact rings electrically connected tosaid sensing means and said electric connecting device includes acorresponding number of sliding contacts coupled to said sliding rings.